1. Field of the Invention
The invention relates to a high-power radiator, in particular for ultraviolet light, having a discharge chamber filled with a filling gas which emits radiation under discharge conditions and having electrodes which are connected in pairs to one or more high-voltage sources, there being situated between two electrodes which are at different potential dielectric material which is adjacent to the discharge chamber.
At the same time the invention makes reference to a prior art as disclosed, for instance, by the European Patent Application having publication number 0 363 832.
2. Discussion of Background
The industrial use of photochemical processes is heavily dependent on the availability of suitable UV sources. The conventional UV radiators yield low to medium UV intensities at a few discrete wavelengths such as, for example, the mercury low-pressure lamps at 185 nm and, in particular, at 254 nm. Truly high UV powers are achieved only from high-pressure lamps (Xe, Hg) which, however, then distribute their radiation over a larger wavelength range. The new excimer lasers have made a few new wavelengths available for fundamental photochemical experiments, but are at present suitable only in exceptional cases for an industrial process for cost reasons.
The European Patent Application mentioned at the outset or, alternatively, the conference paper entitled "New UV and VUV Excimer Radiators" by U. Kogelschatz and B. Eliasson distributed at the 10th Lecture Conference of the Society of German Chemists, Specialist Group on Photochemistry, in Wurzburg (FRG), 18th-20th Nov. 1987, describes a new excimer radiator. This new radiator type is based on the principle that excimer radiation can be produced even in dark electrical discharges, a type of discharge which is used on a large scale industrially in the production of ozone. In the current filaments of this discharge which are present only for a short time (&lt;1 microsecond), noble gas atoms which react further to form excited molecular complexes (excimers) are excited by electron collisions. These excimers live only a few nanoseconds and, on decomposing, give up their bonding energy in the form of radiation whose wavelength range may be in the UV-A, UV-B, UV-C or even in the visible spectral range, depending on the composition of the filling gas.
In the most recent past, the demand for such high-power radiators has increased because the particular properties of the radiator have opened up many new fields of application in chemical and physical process technology, in the graphical trade, for coatings etc. There is therefore a great need for economical and operationally reliable UV radiators, if possible of modular construction.